Orthogonal frequency-division multiplexing (OFDM) is an example of a multi-carrier transmission technique that uses symbol-modulated orthogonal subcarriers to transmit information within an available spectrum. Many modern digital communication systems, including wireless local-area networks (WLANs), are using symbol-modulated orthogonal subcarriers as a modulation scheme to help signals survive in environments having multipath reflections and/or strong interference. One problem with many conventional systems that use symbol-modulated subcarriers is that channel bandwidth is limited to the bandwidth of the individual channels. Some conventional wireless communication systems, such as WLANs that implement OFDM communications, communicate using channels that may only have about a 20 MHz bandwidth. Thus, there are general needs for systems and methods for wider bandwidth communications.